diff --git a/cmake/UnitTest.cmake b/cmake/UnitTest.cmake
index 782dad9..d557eb0 100644
--- a/cmake/UnitTest.cmake
+++ b/cmake/UnitTest.cmake
@@ -4,14 +4,44 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
-include_guard(DIRECTORY)
+#[===[.rst:
+UnitTest CMake module
+---------------------
 
-# Trying to set CLANG_LIBRARY_PATH using the following methods
-# 1. Using cache or command line definition
-#    Show warning if environment variable is also set but has different value
-# 2. Copying the value of CLANG_LIBRARY_PATH environment variable if set
-# 3. find_package (llvm-config, common paths or Windows registry)
-# If none of the above steps succeeded CMake emits a fatal error and stops
+Control flow
+^^^^^^^^^^^^
+
+1. Setting :cmake:variable:`CLANG_LIBRARY_PATH`
+
+  1. Using :cmake:variable:`CLANG_LIBRARY_PATH` CMake variable
+
+  2. Using ``CLANG_LIBRARY_PATH`` environment variable
+
+  3. Trying to find by ``find_package`` function which calls :cmake:module:`FindLibClang`.
+
+2. Checking if ``c-picker`` command is available
+
+
+Variables
+^^^^^^^^^
+
+The module sets the following variables while it's checking its prerequisites.
+
+.. cmake:variable:: CLANG_LIBRARY_PATH
+
+libclang directory for c-picker
+
+.. cmake:variable:: CPICKER_COMMAND
+
+Path of c-picker executable which is part of the c-picker pip package.
+
+
+Functions
+^^^^^^^^^
+
+#]===]
+
+include_guard(DIRECTORY)
 
 set(CLANG_LIBRARY_PATH_HELP "libclang directory for c-picker")
 
@@ -42,15 +72,71 @@
 	message(FATAL_ERROR "Please install c-picker using pip")
 endif()
 
-# Global dependencies:
-#   Variables
-#     CPICKER_COMMAND: command of the c-picker
-#     CPICKER_CACHE_PATH: root directory of the c-picker generate files
-#     UNIT_TEST_COMMON_SOURCES: common source files for every test build
-#     CLANG_LIBRARY_PATH: libclang directory for c-picker
-#   Modules
-#     CTest module should be included in the root CMakeLists.txt before calling this function
+#[===[.rst:
+.. cmake:command:: unit_test_add_suite
 
+  .. code-block:: cmake
+
+    unit_test_add_suite(
+    	NAME test_name
+    	SOURCES source_files
+    	INCLUDE_DIRECTORIES include_directories
+    	COMPILE_DEFINITIONS defines
+    	DEPENDS dependencies
+    )
+
+  The ``unit_test_add_suite`` CMake function provides a convenient interface for
+  defining unit test suites. Basically its input is the test source files, include
+  paths and macro definitions and it internally does all the necessary steps to
+  have the test binary registered in CTest as a result.
+
+  Control flow:
+
+  1. Adding new executable named ``NAME``
+
+  2. Iterating throught ``SOURCES``
+
+     1. If it's a normal source file add to the executable's source list
+     2. If it's a YAML file add as a c-picker custom command and add the generated
+        file to the executable's source list
+
+  3. Setting include directories
+
+  4. Setting defines
+
+  5. Adding extra dependencies of the test build
+
+  6. Adding executable to the system as a test
+
+  Inputs:
+
+  ``NAME``
+    Unique name of the test suite
+
+  ``SOURCES`` (multi, optional)
+    Source files
+
+  ``INCLUDE_DIRECTORIES`` (multi, optional)
+    Include directories
+
+  ``COMPILE_DEFINITIONS`` (multi, optional)
+    Defines
+
+  ``DEPENDS`` (multi, optional)
+    Extra targets as dependencies of the test build
+
+  Global dependencies:
+
+  ``CPICKER_CACHE_PATH``
+    Root directory of the c-picker generated files
+
+  ``UNIT_TEST_COMMON_SOURCES``
+    Common source files for every test build
+
+  ``CTest``
+    Built-in testing module of CMake
+
+#]===]
 function(unit_test_add_suite)
 	set(_OPTIONS_ARGS)
 	set(_ONE_VALUE_ARGS NAME)